Eggs on Ice

By Anita Hamilton

Christia Murdaugh sounds like a typically proud mother when she talks about her little girl Sydney Grace-Louise. "She loves school. She loves to sing. She loves to run and play." But Sydney is hardly your typical 4-year-old. And Christia, 33, is only slightly exaggerating when she calls Sydney her "miracle baby."

That's because when Sydney was born on May 8, 1998, she made medical history as the first child in the U.S. born from her mother's frozen egg. While thousands of children had already been produced from frozen embryos, only one other child in the U.S. had been born from the far more delicate frozen egg, and that egg had come from a donor.

Since then, roughly 40 more babies around the world have been born from frozen eggs, raising hope that what has long been considered the Holy Grail of fertility research might someday become a real alternative for women who want to get pregnant after their most fertile years have passed. Unlike embryo freezing, egg freezing doesn't require that women choose the baby's father years in advance.

Now a Los Angeles clinic wants to bring that hope one step closer to reality by opening the first for-profit egg-freezing operation in the country. "It's like an insurance policy," says Dr. Thomas Kim, medical director of the CHA Fertility Center, which wants to start freezing the eggs of women ages 35 and younger beginning this fall for about $8,000. "If they are willing to do it, we are happy to give them the service."

But the center's ambitious plans are sparking a fierce debate among fertility researchers. Is egg banking a godsend for anxious women or a recipe for heartbreak and failure? Kim claims he has the medical results to justify egg banking, and he has several healthy babies to prove it. Critics insist that it will be years before egg freezing will be ready for prime time. "It's a shot in the dark," says Dr. Richard Paulson, chief of reproductive endocrinology and fertility at the University of Southern California's School of Medicine.

With success rates for live births from frozen eggs ranging wildly (anywhere from 1% to 20%, vs. the 30% to 50% rates for in vitro fertilization using both fresh eggs and sperm), it's not hard to see Paulson's point. Even the kindest critics say women would be wiser to wait until more research is done before laying down the cash and taking the powerful fertility drugs needed to retrieve the eggs in the first place. "As a clinician, you so desperately want to help," says Dr. Thomas Toth, a reproductive endocrinologist at Harvard Medical School, "but first we need to make sure it's safe."

The problem with freezing and thawing unfertilized eggs is that it's notoriously hard to do without destroying the eggs in the process. A human egg is a single, liquid-filled cell that is extremely sensitive to temperature changes; ice crystals can easily rupture cell walls, and the solutions used to preserve the egg sometimes wind up destroying it instead. Also, the egg's chromosomes are in a particularly exposed state. If the meiotic spindle--which holds the chromosomes together and pulls them apart as the egg develops--breaks down, as it tends to do when the egg is frozen and later defrosted, then nothing can be done to save it.

That's why success rates with egg freezing have been so dismal. In Italy, the University of Bologna's Infertility and IVF Center leads the world with an impressive 27 frozen-egg babies. But with more than 600 women each year undergoing the egg-freezing procedure there, the center's past success rates have been as low as 1%. Even Reproductive Biology Associates, the Atlanta clinic where Christia Murdaugh froze her eggs back in 1997, has all but dropped out of the field. Of 30 patients, only two delivered healthy babies. A third had a miscarriage, and the other 27 never got pregnant at all. "There is a lot of hype about this," says Dr. Hilton Kort, co-founder of the clinic.

But CHA's Kim and Dr. Eleonora Porcu at the University of Bologna both say recent technical advances have boosted success rates to the same level as embryo freezing, which is about 20%. In Porcu's most recent studies, 70% to 80% of the eggs survived the defrosting process without breaking down. Kim puts the current frozen-egg birth rate at 21%, based on a recently completed study in which 6 out of 28 women in South Korea became pregnant and later gave birth. One even had twins.

Both teams use similar approaches to egg freezing. After retrieving as many as 20 eggs from a woman by stimulating the ovaries with fertility drugs, researchers dip the eggs in a cryoprotectant (a kind of antifreeze) and then a sugar solution, which pulls water out of the cells by osmosis. Then the cell is stored in liquid nitrogen at -320[degrees]F until it is ready to be used.

Kim and his team use a 10-minute, fast-freezing process called vitrification that he says reduces the chance of ice-crystal formation. Porcu, on the other hand, claims comparable results with a slow-freezing technique that takes about two hours and uses more highly concentrated preservatives.

As fertility doctors know, however, success rates are notoriously hard to gauge. An in vitro center can tip the odds by selecting only the most promising candidates, or it can hurt its numbers by specializing in high-risk cases. So even if the latest improved success rates hold up to scientific scrutiny when they are published later this year, it's probably too soon to draw any broad conclusions.

It's also too soon to tell what complications might arise. Even now, nearly 24 years after the first test-tube baby was born and with more than 30,000 children in the U.S. conceived in vitro each year, a controversial study recently suggested that those babies have a higher risk of genetic damage. "We need to have 700 or 800 babies to prove statistically that there is no increase in birth defects [for frozen-egg babies]," says Dr. Michael Opsahl of the Genetics and IVF Institute in Fairfax, Va. Kim doesn't buy that argument: "The bottom line is, Can you produce a baby? We say yes." He adds that the chromosomal tests done on his babies have so far come out normal.

So how does a would-be mom decide what to do? If she is a young woman facing imminent infertility from cancer treatments or other medical problems, then you could argue that even unknown odds are better than none. Otherwise, it's important to understand that many other options exist--from embryo freezing to sperm donation--with much better track records.

Of course, our life-changing decisions are rarely that rational. For some women, even a small chance of having their own baby may be worth all the risks and uncertainties in the world. "When you so desperately want a child, you are willing to take a chance," says Christia Murdaugh. She, for one, is glad she did.